Plastic blow moldings which are normally utilized to provide containers are manufactured in accordance with one method by extruding a hollow tubular parison of hot plastic between open portions of a mold which is then closed prior to introducing pressurized air into the interior of the parison. This pressurized air blows the parison outwardly to the shape of a cavity defined by the closed mold portions so as to thereby provide a blow molding that is removed by opening the mold. Excess plastic material referred to as flash is conventionally removed by a reciprocally movable knife in a guillotine fashion to further process the blow molding. At a dispensing neck of the blow molding, further finishing is often also required and is conventionally performed by a rotary reamer that produces plastic particles some of which are received within the interior of the blow molding. These plastic particles must be removed prior to completion of the blow molded article, which is usually performed by either turning the blow molding upside down and blowing air into it so that the cooperation of gravity and the blowing air cleans the interior of the blow molding. These reaming and plastic particle removal operations add to the cost of the completed blow molded article and thus must be born by the ultimate consumer.